1. Field of the Invention
The present invention relates a printing apparatus, a print control method, and a program.
2. Description of the Related Art
Pressure-sensitive paper, which is specially treated paper, is used to make copies of actual autograph contents on a plurality of sheets of the paper using writing pressure. Conventional pressure-sensitive paper has been used as a mechanism that carbon paper on which special ink using carbon for copying is applied is placed between sheets, and writing pressure is applied on the sheets to deposit the ink of the carbon paper on the sheets. However, carbonless copy paper that can make copies without using the carbon paper has been developed and widely used.
The carbonless copy paper typically consists of three types of sheets called a top sheet, a middle sheet, and a bottom sheet, which are typically arranged in an order of the top sheet on top, the middle sheet in the middle, and the bottom sheet on the bottom. Copying is performed using a chemical reaction of a color former and a color developer instead of carbon. The top sheet is coated only on its back side with a micro-encapsulated color former. The middle sheet is coated on its front side with a color developer and on its back side with the color former, respectively. The bottom sheet is coated only on its front side with the color developer.
When writing pressure is applied, such as with a ballpoint pen, on the top sheet where the sheets are sorted in the order of the top, middle, and bottom sheets, the microcapsules coated on the back sides of the top sheet and the middle sheet are broken. The color former causes chemical reactions with the color developer coated on the front sides of the middle sheet and the bottom sheet respectively. In this way, color appears. Since the carbonless copy paper has such a mechanism, the order of the sheets is important. For example, if the bottom sheet is placed on the top sheet and characters are written from the top to the bottom sheet, the characters are not copied on the bottom sheet. Thus, the sheets are designed to prevent incorrect use, for example, by coloring the top sheet, the middle sheet, and the bottom sheet different colors respectively.
Some carbonless copy paper are sold separately as top sheets, middle sheets, and bottom sheets respectively, and some carbonless copy paper is sold as one set of the three types of sheets sorted in the correct order. In the latter case, various sets can be provided, for example, the number of the middle sheets can range from zero sheets to multiple sheets. However, since the mechanism uses writing pressure or printing pressure, if the number of the middle sheets is too large, the pressure is not sufficiently transferred, and the copy is not properly made. Therefore, the number of the middle sheets is usually up to three or four (five or six in all).
An example of printing using the carbonless copy paper will now be described. In this example, a set containing two middle sheets is set on a sheet feed tray of an image forming apparatus. In this state, if a job for a product that includes one middle sheet is input, first, one top sheet and one middle sheet are supplied from the sheet feed tray in the order, and printing is performed. Then, the image forming apparatus tries to print on the bottom sheet. However, since one unnecessary middle sheet remains on the sheet feed tray, the unnecessary middle sheet is discharged to the outside of the image forming apparatus. Then, the bottom sheet is supplied and printing is performed.
If a job for a product that includes three middle sheets is input, first, one top sheet and two middle sheets are supplied from the sheet feed tray in that order, and printing is performed. Then, since one more middle sheet is necessary, the apparatus tries to perform printing on a middle sheet. However, an unnecessary bottom sheet and the top sheet of a second set still remain on the sheet feed tray. These unnecessary sheets are discharged to the outside of the image forming apparatus, and printing is performed on the middle sheet of the second set. Further, the image forming apparatus tries to print on the bottom sheet. However, since one unnecessary middle sheet remains on the sheet feed tray, the unnecessary middle sheet is discharged to the outside of the image forming apparatus. Then, the bottom sheet is supplied and printing is performed.
The method for performing printing while unnecessary sheets are discharged to the outside of the image forming apparatus includes, for example, a method for printing on an index sheet while discharging an unnecessary index sheet to the outside of the image forming apparatus (see, Japanese Patent Application Laid-Open No. 2008-201033). The index sheet is usually sold as one set of a plurality of sheets sorted in a predetermined order. However, in generating a product using the index sheets, not all of the one set is always used. By automatically discharging the unnecessary index sheets to the outside of the image forming apparatus while performing printing, the work of adjusting a bundle of index sheets depending on the product is reduced.
In performing the above-described operation of discharging the unnecessary sheets, in order to prevent the sheets that are discharged as unnecessary sheets and the sheets associated with the print job from being mixed up, the sheets are typically output to different discharge destinations respectively. However, in some cases, the operation of switching the discharge destinations takes time. For example, it is assumed that a printing apparatus has one discharge path, and a post-processing device connected to the discharge path has two discharge trays. The discharge tray that a discharged sheet, which has passed through the discharge path, is stacked on can be controlled by controlling positions of the discharge trays. However, if the discharge destinations are switched by controlling the positions of the discharge trays, it takes time to control the tray positions. As a result, the operation of switching the discharge destinations requires a long processing time. Further, in printing a plurality of copies of the print job, the discharge destination switching operation is performed in each print copy, and the total productivity is largely deteriorated.